Substituted 1,5-benzodiazepines are known having the formula ##EQU1## wherein R' and R" are hydrocarbon radicals, as reported, for example, by Barltrop et al, J. Chem. Soc. 1959 p. 1132. Their synthesis by reaction of o-phenylene diamine with beta-diketones was reported by Thiele and Steimmig, Ber. 40 955 (1907). To the best knowledge of present inventors, benzodiazepines substituted by fluorinated radicals, in particular by perfluorinated radicals, have not been disclosed.